Manually set output as clock by setting the CLOCK attribute +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ The following shows that ``output wire o`` is given the ``(* CLOCK *)`` attribute. .. symbolator:: output_attr_clock.sim.v | .. no-license:: output_attr_clock.sim.v :language: verilog :caption: tests/clocks/output_attr_clock/output_attr_clock.sim.v As such, the ``is_clock`` attribute of the ``o`` port is set to 1. .. literalinclude:: output_attr_clock.model.xml :language: xml :caption: output_attr_clock.model.xml